DC-DC converters typically include one or more switches that are selectively actuated to provide a controlled DC output voltage or current based on a received DC input. The output power is regulated by controlling the pulse width or on time of the signaling provided to the converter switch or switches according to an error signal representing the difference between the actual output voltage or current and a desired value (pulse width modulation or PWM). A capacitor is typically connected at the converter output in parallel with a driven load, in order to stabilize the converter output voltage and provide a source for load current. At power up, however, the output capacitor is initially discharged, and the difference between the output voltage and the desired value may be large, causing the pulse width modulation control to provide large amounts of current to the output. The output capacitor may thus experience high levels of inrush current during startup, which may damage or degrade the output capacitor. Soft starting techniques may be used to limit the amount of inrush current provided to the output capacitor during startup, including the provision of on-board (internal) soft start circuitry in the pulse width modulation controller. However, internal soft start circuits typically provide a fixed or pre-determined soft start time during which the output current is limited, and the desired soft start timing specification may be different for different applications. For example, the maximum tolerable level of inrush current may be dictated by the particular output capacitor used. Accordingly, a combination of internal and external soft start circuitry may be used, allowing a user to either employ the internal soft start circuit and the associated fixed soft start time, or to connect one or more external components to the pulse width modulation controller to set a different (e.g., longer) soft start time, thereby further limiting the output capacitor inrush current. The internal and external soft start circuitry is often connected to the closed loop feedback error amplifier circuit, in order to artificially modify (e.g., lower) the error signal from which the PWM switching control signal or signals is/are generated. However, accommodating both internal and external soft start circuitry requires two additional inputs to the error amplifier circuitry. The input transistors of the error amplifier are typically of very large dimensions in order to minimize input offsets, and thus a larger integrated circuit die size is needed if four error amplifier inputs are used. In addition, the input transistors of the error amplifier are typically closely matched, such as in differential input stage implementations used in comparing a setpoint or reference value with a feedback value, and the provision of a large number of error amplifier inputs may result in matching difficulty due to the large device sizes. Accordingly, there is a continuing need for improved control circuits for pulse width modulation control of DC-DC converters with internal as well as external soft start circuits, without increased device size and device matching problems associated with conventional control circuits.